One of the great concerns in the nuclear power field throughout the world is the safe disposal and isolation of used fuels from reactors or waste streams from reprocessing plants. In particular, entrapment of highly mobile radionuclides such as iodine (129I) and technetium (99Tc) produced from a fission process and subsequent capturing and immobilization of these radionuclides in an appropriate waste form is a great technical challenge because of the high mobility of these radionuclides and the difficulty in incorporating them into any existing waste forms such as glass, ceramics, and grout. Iodine (129I) and technetium (99Tc) both have long half-lives and can exist as gaseous or anionic species that are highly soluble and poorly sorbed (absorbed or adsorbed) by natural materials. Waste forms are probably the only engineered barrier to limit their release into a human-accessible environment after their disposal. Furthermore, a majority (>99%) of 129I will enter into the dissolver off-gas stream during fuel reprocessing. It is thus highly desirable to develop a material that can effectively entrap gaseous iodine during the off-gas treatment.
Thus, further advancements are needed in the area of radioactive nuclei capture and immobilization.